Pressure sealed transducer for automotive vehicles

Abstract

The present invention relates to a transducer with a piezoelectric crystal for parking aids in automotive vehicles. Such transducers must be sealed against steam jets. This object is achieved by the present invention by means of a plug including projections forming an evacuatable chamber in conjunction with the inner wall of a housing bowl. Developments of the present invention relate to the protection and sealing of the diaphragm retainer, which is part of the transducer, against moisture and mechanical displacement due to vibrations and other environmental influences.

We claim: 
     
       1. A transducer of the type including a diaphragm and a diaphragm retainer which carries an oscillator wherein said diaphragm retainer is mounted into the opening of a plug made of an elastic material such that the bottom of the diaphragm retainer provides ease of access, and the plug is mounted into an open end of a housing, comprising at least two spaced circumferential projections extending from said plug, wherein said projections form walls of a first circumferential chamber. 
     
     
       2. A transducer as claimed in claim 1, wherein the hollow-cylindrical wall of the said plug includes a cylindrical wall having at least one radial bore which is spaced from the two circumferential projections. 
     
     
       3. A transducer as claimed in claim 1, wherein said housing includes at least one radial aperture and the at least one radial bore and the radial apertures terminate into a first chamber. 
     
     
       4. A transducer as claimed in claim 2, wherein, the diaphragm retainer inclues at least two spaced circumferential grooves which are arranged on either side of the radial bores of said cylinder wall in the mounted condition of the transducer. 
     
     
       5. A transducer as claimed in claim 1, wherein the plug has three projections forming the first and a second chamber. 
     
     
       6. A transducer as claimed in claim 5, wherein the radial bores of said cylinder wall and the radial apertures terminate into a first chamber of two chambers said first chamber being arranged in proximity to the open end of the housing bowl. 
     
     
       7. A transducer as claimed in claim 4, wherein a side wall of the plug opening has two circumferential attachments which are associated with the grooves of said diaphragm retainer. 
     
     
       8. A transducer as claimed in claim 3, wherein the radial bores of said cylindrical walls and the radial apertures are offset in relation to each other. 
     
     
       9. A transducer as claimed in claim 1, wherein an end of the plug remote from the diaphragm retainer carries an electric circuit having its electrical components project into a housing chamber that is defined by the plug and the housing.